Stucco News

Question and answers on Stucco and Plastering-- April, 2013

Veneer plaster

My name is Ryan
Frisbie and I have been doing mainly interior thin coat
plaster for the last 8 years. I stumbled upon your
webpage and looked through all of the jobs you have
done, I was blown away. I live in Michigan and here it
is so hard to convince people how much better real
plaster is over drywall and eifs. Throughout my career
like I said I have done mainly thin coat plaster with a
base coat and lime finish over blue board either smooth
or textured but I have also done conventional
plastering, exterior cement plaster, lots of cornice
work, off-sets and medallions/rosettes. Here in Michigan
we mainly only work in multi-million dollar custom
homes, they seem to be the only people willing to pay
for plaster. Right now we are actually doing a house
where the home owner is replicating a house from the
1700's from the siding to the light fixtures the windows
you name it its all 1700's style. The house was all
framed with rough cut lumber to create rolls and hollows
in the walls, we went through and hung the whole house
with wood lath and applied grounds and we just started
browning it with a sand mud brown coat. I am just so
glad to have found someone who is as adamant as I am
about the quality of plaster over the new age cheaper
lower quality products, I can't even begin to tell you
about how many calls I get from home owners asking me to
fix a water damaged eifs jobs or builders calling me in
to come fix an awful drywall job. One way I show home
owners how strong plaster is I drag a six inch drywall
knife down browned wall that set over night and sparks
fly off the knife and it doesn't damaged the basecoat,
it usually blows them away then I tell them now try that
with drywall and see what happens. Well I have taken up
enough of your time keep up the good work!

Veneer
plaster, sometimes called thin coat plaster,
has been around since the 1950's. It is a great
alternative to
drywall, and is less expensive than
conventional lath and plaster.
The surface is durable, but you can
still kick a hole in the wall. For high abuse
surfaces like hospital corridors, jails, etc.
conventional plaster should be used.
There are two methods, the two coat
system where a thin plaster basecoat is used, and a
one coat system, where the finish coat is
directly applied to the
board.

Veneer plaster is
applied on blue board, which is wallboard
that is color coded blue. Examples of blue board are "Imperial
board" from United States Gypsum and "Kal-core"
from National Gypsum. Veneer plaster base should never
be confused with the blue mold resistant wallboard that
has come out in recent years, or green board, a water
resistant board for drywall.
Plaster finishes for the One coat system
are very hard and contain fine sand. Recommended
finish materials for one coat are Diamondfinish,
Imperialfinish and Norfolkveneer.
Other finish materials such as lime and gauging plaster,
or Red top finish plaster should neverbe used directly on blue board without a
basecoat. They are weak, the joints will crack and the
material scrapes off the wall easily.Diamond finish and Imperial finish are
very difficult to work with, and may be fine for a rough
finish, but it is hard to achieve a suitable smooth
trowel finish. Norfolk veneer, however provides a
suitable finish with one coat. I found it hard to
trowel, meaning it is like pushing a car with your
trowel.
I think Norfolk Veneer is made in Norfolk,
Virginia and is widely used in the Tidewater area
of
Virginia, where a lot of plaster is still used. It is
also used frequently in Roanoke and Richmond.
I had to drive all the way to the other side or Richmond
to buy it. Norfolk veneer is unknown here
in Northern Virginia, and in fact, plaster is
pretty much unknown here. I think we are the
last ones
here that still plaster houses.
The one coat still allowed us to finish a huge
kitchen and dining room area the same day. They
were putting on the wood trim and cabinets the next.
Before applying the finish, the joints must be taped.
Using the the two coat method, we use a self
stick mesh tape. When I worked for a plaster
company years ago in Richmond, the old buzzards
insisted the staple on tape was better, so we didn't use
the self sticking kind.
I have seen Norfolk Veneer jobs that had cracks
at the joints when they used mesh tape.
Preferable results are achieved by using paper drywall
style tape and Durabond, a setting type
drywall compound. I think USG changed the name of
Durabond to "Sheetrock" compound.
This should not be confused with Easy Sand
setting compound, that is weak and too soft
for
this use.
The procedure is to tape the joints with Durabond, and
fill in the butt joints and deep areas.
As soon as this sets up, the finish plaster can be
applied.
The two coat method is our method of choice. The
basecoat allows filling and straightening of
deep areas and provides incredible strength for
a thin coat. Also, the basecoat is hard and porous, and
supports practically any kind of plaster finish.

The procedure is to tape the
joints with a mesh tape, then scratch a
coat of veneer basecoat mortar on the joints and
immediately come back and coat the whole wall.
The wall can be troweled being careful to leave
the surface rough enough for a good bond for the
finish.
Another method is to put on a thin scratch coat
and
a thin double up coat, and rough the surface by
dragging a broom across.
This method allows for a thick basecoat
and a thin finish coat.

Years ago, we used to use Red Top finish plaster,
or Gold Bond finish plaster over the
veneer basecoat. This premixed finish plaster was fast
because it could mixed with a drill, and troweled easy,
unlike Imperial and Diamond. The problem with these
finish plasters is that they are gauged
too light, meaning they contain about three parts lime
and one part gauging. This leads to catfaces
(voids) due to shrinkage, and a comparatively weak
surface.
Most plasterers I know just use a lime and gauging
or a lime and molding plaster finish.
This produces a far superior product to the premixed
finish plaster, even though it isn't recommended
by the manufacturer. This allows the plaster to
gauge the finish mortar heavy,
meaning about half and half. This is what we do and have
excellent results.
Another finish that we do a lot of is Keene's
Cement, lime and fine white sand. Keene's cement
is a gypsum plaster that sets slow, allowing large areas
to be done with a single batch.
This is preferred for color plaster finishes, which we
do a lot of, and for textures.
Keene's is used a lot in California where
decorative textures are preferred.
Another advantage of Keene's is that is super hard, and
water resistant, allowing the walls to be scrubbed.
Veneer plaster isn't cheap, but is quite a value. One
problem is the price of plaster materials has
nearly tripled in last ten years making plaster out of
reach for some budgets.
Bob Vila did our industry a lot of good as a salesman.
Nearly ever project he did had veneer plaster.
Enough for now, Please keep checking back for more.